A tin can wall is a wall constructed from tin cans, which are not a common building source. The cans can be laid in concrete, stacked vertically on top of each other, and crushed or cut and flattened to be used as shingles. They can also be used for furniture. Tin cans can form the actual fill-in structure (or walls) of a building, as is done with earthships. Tin cans have not been around for a long time, and neither have their building methods. The two main structural methods for building with tin cans are by laying them horizontally in a concrete matrix and by stacking them vertically.
History Tin can building in New Mexico originated in the early 1980s as a response to the massive amounts of trash being discarded and the wasteful nature of common building practices. Tin can construction was an attempt to utilize a readily available resource that was normally sent to landfills or recycling centers. This led to various experiments in tin can building, including space-filler between wooden frames in traditional house styles and creating domes and archways using cans and cement. Over time, more simplified and practical methods were developed, such as the earthship tin can wall. The main person behind these efforts was Mike Reynolds, also the creator of the earthship building method.
Construction A “traditional” earthship tin can wall is made by horizontally stacking tin cans in a concrete matrix. The cans are laid side by side and in alternating rows, similar to bricks. This is done simply and efficiently, using batches of concrete between the cans. The consistency of the concrete must be relatively thick, so as to hold its form and the tin cans in place. A surprisingly large number of cans are required. The method for stacking the cans involves creating a row of cans separated by hand-formed “lumps” of concrete. The layout of a row is can, concrete, can, etc. This is then repeated, except that the alternating pattern is reversed, so that every can is laid on top of a concrete “lump” below it. This continues until completed, or the weight of the wall and the hardness of the cement seem questionable in terms of solidity. At that point it would be wise to wait for the wall to harden, but the laying time for cans and concrete is such that by the time a builder makes it back to an area that was recently laid it has had time to set. It is a judgment call as to whether or not the builder should continue, but by the next day or even later on the same day building can resume.
Materials The materials that go into a tin can wall are simple: mainly tin cans and concrete. Tin cans (now aluminum cans as real tin cans are not as readily available) can be acquired from any recycling center or a local bar. Brick mortar may also be used instead of cement.
Coating Once the wall is completed, the cans and the concrete are covered with a layer of cement or adobe mud mixture. What is applied depends on the location of the wall; if it is located in an area where it will be exposed to water (such as in a bathroom or utility room) it will need to be coated with a concrete layer. If it is located in a living room or bedroom, it can be covered with adobe plaster. A tin can wall that has half of its structure outside (such as the wall of an entrance to a building) will be coated with cement on the outside and adobe on the inside. The shape of the cans (their pull-tabs, etc.) and the roughness of the cement will provide a lath-like surface for the cement or adobe to stick to. This initial layer is “screeded” (scratched with a tool that creates a ridge-like pattern thereby making it easier to apply another coat) and a second layer is added. More layers may be added, but it is up to the builder's judgment and dependent upon the material being applied. In the case of adobe mud, once the initial layer is applied and allowed to harden it will crack and will need additional coats. With cement fewer layers are needed. The basic rule is: the more coats/layers, the stronger and better-looking the wall will be. This can be overdone however. When a tin can wall has been sufficiently coated it will then be “finished” with a fine plaster (lime-based or other), stucco (if the wall is outside), or linseed oil (in the case of adobe). It can also be finished with a clay “slip”, or aliz, which is an earth-based coat that can have natural pigment and fine grains of mica mixed in to produce a beautiful shimmering and organic-looking surface.
Examples An outside tin can insulating wall is a simple design. It is made out of two tin can walls with a layer of solid insulation in the middle. The insulation can vary in thickness, depending on climate and budget. It can be made out of various “green” or sustainable materials or average run-of-the-mill solid insulation. The exposed sides of the tin can walls (those not facing the insulation) are finished using methods aforementioned. The inside part of the wall can be coated with adobe while the outside is finished with concrete and stucco.
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